Device and method for testing pressure of hydraulic tools

ABSTRACT

Devices and methods are provided for testing and maintaining hydraulic tools and, in particular, devices and methods for testing and maintaining hydraulic forcible entry tools that are used to forcibly open locked doors, for example, in emergency situations.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-in-Part of U.S. patent applicationSer. No. 13/931,893, filed on Jun. 29, 2013, which claims priority toU.S. Provisional Patent Application No. 61/665,918, filed on Jun. 29,2012, and to U.S. Provisional Patent Application No. 61/745,555, filedon Dec. 22, 2012, the disclosures of which are incorporated herein byreference.

TECHNICAL FIELD

The field generally to devices and methods for testing and maintaininghydraulic tools and, in particular, devices and methods for testing andmaintaining hydraulic forcible entry tools that are used to forciblyopen locked doors, for example, in emergency situations.

BACKGROUND

In emergency situations, police, firefighters, and other firstresponders may need to forcibly enter as building or dwelling to gainaccess in order to save lives. Chic common method of forcible entryinvolves forcibly opening a locked door. In general, emergency personneland first responders typically rely on a number of different devices toforce entry through a locked door into a dwelling or building. Pryingtook, such as “Halligan” tools and crowbars are common took used tobreach doors and windows. A Halligan is a special tool commonly used byfirefighters for prying, twisting, punching, or striking,

Other tools that are commonly used to forcible open locked doors aregenerally referred to as “hydraulic forcible entry tools”. These toolsare generally designed to forcibly open locked doors that open ininwardly (right or handed inwardly swinging doors), as well as forciblyopen other types of non-hinged doors such as elevator doors that can bespread apart. There are various commercially available hydraulicforcible entry tools. Currently, the most commonly used commerciallyavailable hydraulic forcible entry tools are known as the “HYDRA RAM”and the “RABBIT TOOL” These hydraulic forcible entry tools are shown inFIGS. 1A, 1B and 2.

In particular, FIGS. 1A and 1B illustrate a hydraulic forcible entrytool (10) that is sold under the name brand “HYDRA RAM.” The hydraulicforcible entry tool (10) comprises a first handle (12), a second handle(14), a hydraulic housing (16), spreading jaws (18), and a movablepiston (19). As further shown in FIG. 1B, the spreading jaws (18)include a fixed jaw member (18A) that is connected to the hydraulichousing (16), and a movable jaw member (18B) that is connected to an endof the movable piston (19). FIG. 1A illustrates the hydraulic forcibleentry tool (10) in a non-extended position wherein the piston (19) isretracted into the hydraulic housing (16) and wherein the fixed andmovable jaws (18A) and (18B) are joined together forming a sharp bladetip (18C), FIG. 1B illustrates the hydraulic forcible entry tool (10) inan extended position wherein the piston is extended out from thehydraulic housing (16) and wherein the fixed and movable jaws (18A) and(18B) are separated.

In operation, starting from the non-extended position shown in FIG. 1A,the hydraulic forcible entry tool (10) would be positioned at some pointof the door where a door lock (e.g., dead bolt, door handle, etc.)exists, with the sharp edge (18C) of the jaws (18) forcibly insertedbetween the door and a door stop. In this position, the bottom of thehydraulic housing (16) would rest against the door stop/frame (parallelwith the door frame) and the outer surface of the movable jaw (18B)would be pushed up flat against the surface of the door.

The individual using the tool (10), holding both handles (14) and (12),would start pumping the movable handle (12) hack and forth to operate ahydraulic pump within the housing (16), causing the piston (19) toextend out from the housing (16). With the fixed jaw (18A) pressingagainst the inner surface of the door stop and the movable jaw (18B)pressing against the door, the door is forcibly pushed open as thepiston (19) extends further out until the door is forcibly pushed openby, e.g., breaking the lock. A hydraulic forcible entry tool (10) asshown in FIGS. 1A and 1B sold under the name brand of “HYDRA RAM”provides a jaw spread of 4 to 6 inches (extension of piston (19)) with arated maximum spreading force of 10,000 psi.

Moreover. FIG. 2 illustrates another type of hydraulic forcible entrytool (20) that is known as the “RABBIT TOOL” FIG. 2 shows the hydraulicforcible entry tool (20) in operation, forcibly opening an inwardlyswinging door (200). The hydraulic forcible entry tool (20) comprises ahandle/hydraulic housing unit (22), a high-pressure hose (26) connectedto a pump (not shown), spreading jaws (28), a slidable bracket/guide(24) and a movable piston (29). The spreading jaws (28) include a fixedjaw member (28A) that is connected to the housing (22) and a movable jawmember (28B) that is connected to an end of the movable piston (29).

The operation of the hydraulic forcible entry tool (20) is similar tothat discussed above for the hydraulic forcible entry tool (10) of FIGS.1A and 1B. More specifically, in operation, starting from thenon-extended position, the hydraulic forcible entry tool (20) would bepushed against the door (200) and a door frame (202) at some point ofthe door (200) where a door lock (e.g., dead bolt, door handle, etc.)exists, with the sharp edge of the jaws (28) forcibly inserted betweenthe door (200) and a door stop (204). The individual using the hydraulicforcible entry tool (20) would hold the tool (20) in position againstthe door (200) and door frame (202), and the pump apparatus (not shown)would be started to cause hydraulic fluid to be pumped through the hose(26) into the housing (22) causing the piston (29) to movably extend outfrom the housing (22). As shown in FIG. 2, with the fixed jaw (28A)pressing against the inner surface of the door stop (204) and themovable jaw (28B) pressing against the door (200), the door (200) isforcibly pushed away from the door stop (204) as the piston (29) isextended until the lock(s) is/are broken.

In order to ensure proper operation of a hydraulic forcible entry toolsuch as described above, it is important to inspect and maintain thetool on a frequent basis. The inspection and maintenance of hydraulicforcible entry tools on a routine basis (e.g., weekly) is vital toensuring that the tools are battle ready and will not fail when they areused in an emergency situation. One way to properly inspect and maintainas hydraulic forcible entry tool is to frequently test the tool under a“load” Testing a hydraulic forcible entry tool under a “load” servesvarious purposes.

For example, operating a hydraulic forcible entry tool under a “load”forces the oil to properly lubricate the internal hydraulic gaskets.Failures are common in hydraulic forcible entry tools that have sataround for long periods of time without use, causing the internal sealsto dry out and crack, and therefore leading to possible failure. Someindividuals attempt to test and maintain a hydraulic forcible entry toolby simply pumping the tool and extending the piston under no tension orload, and then retracting the piston. However, this operation does notadequately force the oil up into the internal gaskets to keep themlubricated and moist and prevent the internal gaskets/seals fromcracking. When the internal seals in the hydraulic tool thy out, theytend to crack and become brittle over time, which weakens the seals andresults in tool failure when used under a load.

Furthermore, operating as hydraulic forcible entry tool under a “load”ensures that the tool will actually work properly and not fail underload conditions. Indeed, even if the tool appears to work properly whenthe tool is operated without a load (i.e., the piston extends out whenthe tool is pumped), the tool can still result in a failure and not beable provide sufficient spreading force when used in an emergencycondition under a load.

Currently, there are no known devices that provide controlled loadconditions for testing and maintaining hydraulic forcible entry tools.To check a hydraulic forcible entry tool under “load” conditions, someindividuals will place the jaws of the tool between the open jaws of abench vise grip and then operate the hydraulic forcible entry tool untilthe jaws of the hydraulic forcible entry tool press against the jaws ofthe bench vise grip. Other individuals may operate the hydraulicforcible entry tool by Idling objects such as dumpsters, soda machines,or other heavy objects. However, testing and maintain a hydraulicforcible entry tool using these raw techniques can be problematic forvarious reasons.

For example, operating hydraulic forcible entry tool in a vise grip orusing the tool to lift heaving objects can over exert the tool, puttinggreat stress on the tool and damaging the tool's inner seals in waysthat can lead to subsequent premature failures. Moreover, these raw testmethods do not allow an individual to determine with any reasonabledegree of certainty the amount of pressure (psi) that the tool isactually providing at the time of testing. Indeed, even if the hydraulicforcible entry tool does seem to function properly under a given load(e.g., vise grips or lifting an object), the individual testing the toolhas no way of determining how much force the tool is providing under thegiven load. In this instance, even if a hydraulic forcible entry tool iscapable of providing some spreading force under an unknown load, thetool may still be in a current state in which it is incapable ofproviding sufficient spreading force to operate the tool in its intendedmanner, such as forcibly opening a steel door with dead bolts.

SUMMARY

Embodiments of the invention generally include devices and methods fortesting, and maintaining hydraulic tools and, in particular, devices andmethods for testing and maintaining hydraulic forcible entry tools thatare used to forcibly open locked doors, for example.

In one embodiment of the invention, a device for testing a hydraulictool includes a support base, a first fixed plate fixedly connected tothe support base, a second fixed plate fixedly connected to the supportbase, a movable plate, disposed between the first and second fixedplate, and one or more compression springs disposed between the movableplate and the second fixed plate. The movable plate and the first fixedplate are oriented with respect to each other and adapted to engage ahydraulic tool being tested. The movable plate is adapted to be movedtowards the second fixed plate upon actuation of the hydraulic tool andcompress the one or more compression springs to provide a compressionforce that provides a test load for testing the hydraulic tool.

These and other embodiments of the present invention will becomeapparent from the following detailed description of embodiments, whichis to be read in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B illustrate one type of hydraulic forcible entry tool.

FIG. 2 illustrates another type of hydraulic forcible entry tool and itsuse in forcibly opening an inward swinging door.

FIGS. 3A and 3B are schematic perspective views of a device for testingand maintaining a hydraulic tool, according to an exemplary embodimentof the invention.

FIGS. 4A and 4B are side schematic views of a device for testing andmaintaining a hydraulic tool, according to another exemplary embodimentof the invention.

FIGS. 5A and 5B are a side schematic view and perspective view,respectively, of a device for testing and maintaining a hydraulic tool,according to another exemplary embodiment of the invention.

FIGS. 6A and 6B are a side schematic view and perspective view,respectively, of a device for testing and maintaining a hydraulic tool,according to another exemplary embodiment of the invention.

FIGS. 7A and 7B are perspective views of a device for testing andmaintaining to hydraulic tool, according to another exemplary embodimentof the invention.

FIGS. 8A and 8B are perspective views of a device for testing andmaintaining a hydraulic tool, according to another exemplary embodimentof the invention.

FIG. 9 is a perspective view of a device, for testing and maintaining ahydraulic tool, according to another exemplary embodiment of theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

In general, devices and methods for testing and maintaining hydraulictools in accordance with exemplary embodiments of the invention will nowbe discussed in further detail with references to FIGS. 3A, 3B, 4A and4B. The exemplary test devices and methods discussed herein can be usedfor testing and maintaining a hydraulic forcible entry tools such asdiscussed above with reference to FIGS. 1A, 1B, and FIG. 2.

FIGS. 3A and 3B are schematic perspective views of a test device (300)lot testing and maintaining a hydraulic tool, according to an exemplaryembodiment of the invention. As shown in FIGS. 3A and 3B, the testdevice (300) generally includes as support base (310), a first fixedplate (320), a second fixed plate (330), a movable plate (340), and aplurality of springs (350) disposed between the movable plate (340) andthe second fixed plate (320). The first fixed plate (320) comprises afirst member (322) and a second member (324) which form a right angle(90 degrees) fixed plate structure. The second fixed plate (330)comprises as first member (334) that is disposed parallel to the movableplate (340), and a plurality of extended support members (332) that aredisposed perpendicular to the first member (334) to provide support forcompressive forces that are applied to the second fixed plate (330), aswill be described below.

In one embodiment of the invention, the support base (310), first fixedplate (320), second fixed plate (330), and a movable plate (340) aremade of as metallic material such as ⅜ inch or ½ inch thick steel, forexample. The constituent components (322) and (324) of the first fixedplate (320) may be separate elements that are welded together to formthe first fixed plate (320). Similarly, the constituent components (332)and (334) of the second fixed plate (330) may be welded together to formthe second fixed plate (330). The first fixed plate (320) and the secondfixed plate (330) may be welded to the supporting base plate (310). Thesupporting base plate (310) may comprise a plurality of thru-holes (312)formed in corner regions of the base plate (310) so that the test device(300) can be bolted or screwed down to a supporting work benchstructure, for example.

In one exemplary embodiment as shown in FIGS. 3A and 3B, a bolt (360)longitudinally extends within the interior of each spring (350) andpasses through corresponding holes formed in the movable plate (340) andthe flat plate portion (334) of the second fixed plate (330). In theexemplary embodiment shown in FIGS. 3A and 3B, a nut (362) is screwed onto each threaded end of the bolts (360). A plurality of recesses (342)are formed on one surface of the movable plate (340) to a depthsufficient to recess the nuts (362).

The nuts (362) on the threaded ends of the bolts (360) that pass throughthe movable plate (340) are preferably tack welded in place within therecesses (342) so that the nuts (362) and ends of the bolts (360) arefixedly connected to each other and fixedly connected to the movableplate (340). The nuts (362) on the other threaded ends of the bolts(360) that pass o through holes formed in the flat plate portion (334)of the second fixed plate (330) are tack welded to each other, but notto the flat plate portion (334) of the second fixed plate (330). Indeed,while one end of the threaded bolts (360) are fixedly connected to themovable plate (340), the other end of the threaded bolts (360) canslidably move back and forth through holes formed in the second fixedplate (330) while the test device (300) is being used (as furtherexplained below).

In the exemplary embodiment of FIGS. 3A and 3B, the test device (300) isshown to have 5 springs (350) disposed and symmetrically arrangedbetween the movable plate (340) and the flat plate (334) of the secondfixed plate (330), although any number and arrangement of springs may beemployed depending on the application. The springs (350) can be any typeof compression coil spring (helical or conical coil springs, forexample) that exert an opposing force against the movable plate (340) asthe springs (350) are compressed from the movable plate (340) beingpushed towards the second fixed plate (330) when testing a hydraulictool using the test device (300), as will be explained in further detailbelow. The exemplary embodiment of FIGS. 3A and 3B illustrates the useof engine valve springs having threaded rods that pass through thecenter of the valve springs. Other types of commercially available orspecial manufactured compression springs may be employed in a testdevice according to other embodiments of the invention.

Each spring (350) exerts a maximum compression force, so the number ofcompression springs used will vary depending on the maximum amount oftest force that the test device is designed for. In general, theopposing force F exerted by a compression spring as it is compressed canbe determined from Hooke's Law: F=k(L_(free)−L_(def)), where k is thespring constant or force constant of the spring (a constant that dependson the spring's material and construction), L_(free) is the spring freelength, i.e., the length of the compression spring when uncompressed,and where L_(def) is the length of the compression spring in acompressed state. In this regard, the force with which a compressionspring pushes back is proportional to the distance from its free(equilibrium) length.

In the exemplary embodiment of FIGS. 3A and 3B, for example, assumingthat each of the 5 springs (350) is rated to provide 2000 PSI of maximumcompression force, the use of the 5 springs (350) in parallel betweenthe moving plate (340) and the second fixed plate (330) can provide asmaximum rating of about 10,000 psi of test force for testing thespreading force of a hydraulic forcible entry tool, such as discussedabove with reference to FIGS. 1A/1B and 2.

FIGS. 4A and 4B are side schematic views of a device for testing andmaintaining a hydraulic tool, according to another exemplary embodimentof the invention. In particular, FIGS. 4A and 4B illustrate a testdevice (400) for testing and maintaining, a hydraulic tool, which issimilar to the test device (300) of FIGS. 3A/3B in that the test device(400) includes a support base (310), a first fixed plate (320), a secondfixed plate (330), as movable plate (340), and a plurality of springs(450) disposed between the movable plate (340) and the second fixedplate (320).

The test device (400) differs front the test device (300) of FIGS. 3A/3Bin that the test device (400) of FIGS. 4A/4B comprises a plurality ofsprings (450) and a plurality of bolts (or rods) (460) that are separatefrom each other (the bolts are not disposed within the interior of thesprings). The springs (450) are held in place between the movable plate(340) and the flat plate portion (334) of the second fixed plate (330)using a plurality of metallic studs (470) that are fixedly connected(e.g., welded) to facing suffices of the movable plate (340) and theflat plate portion (334) of the second fixed plate (330). The studs(470) are dimensioned (having a diameter) to snuggly fit within theinner region (inner diameter) of the compression springs (450).

The bolts (460) pass through corresponding holes formed in the movableplate (340) and the flat plate portion (334) of the second fixed plate(330). A nut (462) is screwed on to each threaded end of the bolts(460). A plurality of recesses are formed on one surface of the movableplate (340) to a depth sufficient to recess the nuts (462). The nuts(462) on the threaded ends of the bolts (460) that pass through themovable plate (340) are preferably tack welded in place within therecesses so that the nuts (462) and ends of the bolts (460) are fixedlyconnected to each other and to the movable plate (340). The nuts (462)on the other threaded ends of the bolts (460) that pass through holesformed in the flat plate portion (334) of the second fixed plate (330)are tack welded to each other, but not to the flat plate portion (334)of the second fixed plate (330). This allows the bolts (460) to slidablymove back and forth through the holes formed in the second fixed plate(330) while the test device (300) is being used (as shown in FIG. 413).A washer (464) may be used on the ends of the bolts (450).

The operation of the test device (300) of FIGS. 3A and 3B and the testdevice (400) of FIGS. 4A and 4B are the same, and will now be furtherdiscussed with primary reference to FIGS. 4A and 4B. In each of theexemplary test device embodiments discussed herein, the initial distancebetween the movable plate (340) and the flat plate portion (334) of thesecond fixed plate (330) depends, for example, on the spring free lengthL_(free) (length of compression spring when uncompressed) of thecompression springs 350, 450 that are employed.

A specifically shown in FIG. 4A, the first fixed plate (320) is fixedlyconnected to the support plate (310) such that a small gap G (space)exists between the movable plate (340) and the second member (324) ofthe first fixed plate (320) when the springs (450) are in anuncompressed state (i.e., no force is applied to the surface of themovable plate (340)). The small gap G can be in a range of about ⅛ inchto ¼ inch, or any other suitable distance, that would sufficient toinsert the tip of the (non-extended) spreading jaws or blades of ahydraulic forcible entry tool into the gap G when testing the hydraulictool. In some embodiments, the initial gap G can be adjusted by turningthe nuts (462) on the threaded end of the rods (460) to increase ordecrease the distance between the plate elements (334) and (340).

By way of example, starting with the hydraulic forcible entry tool (10)of FIG. 1A in a non-extended position, the sharp blade tip (18C) of thejoined fixed and movable jaws (18A) and (18B) would be inserted into thegap G between the movable plate (340) and the first fixed plate (320).The hydraulic forcible entry tool (10) would be oriented with the bottomsurface of the hydraulic housing (16) resting against the surface of thefirst member (322) of the first fixed plate (322) and with the outersurface of the movable jaw (18B) pushed up flat against the surface ofthe movable plate (340). In this regard, the first fixed support plate(320) of the test device would emulate a doorframe and the movable plate(340) would emulate as door to be forcibly pushed open.

Once in this initial position, the hydraulic forcible entry tool (10)would be operated by pumping the movable handle (12) back and forth tocause the piston (19) to movably extend out from the housing (16). Withthe fixed jaw (18A) held pressing against the first fixed support plate(320) and the movable jaw (18B) pressing against the movable plate(340), the tool (10) would be operated to extend the piston (19) andstart exerting a force F against the movable plate (340), as shown inFIG. 4B, causing the compression springs (450) to compress as themovable plate (340) is pushed towards the second fixed plate (330)

As further shown in FIG. 48, once the movable plate (340) is pushedtowards the second fixed plate (330) the end portions of the bolts (450)slidably pass through holes formed in the flat plate portion (334) andmovably extend out behind the second fixed support plate (330). In oneexemplary embodiment, as shown in FIGS. 3A/38 and 4A/4B, a lower plateelement (344) may be connected (e.g., welded) to the bottom of themovable plate (340). This lower plate element (344) serves severalpurposes. For instance, the lower plate (344) can serve as a means tostabilize the movable plate (340) as it slides back and forth. Moreover,the lower plate (344) can serve as a stop element to limit the amount ofdistance that the movable plate (340) can be pushed towards the innersurface of the element (334) of the second fixed plate (330) (so as tonot over exert the compression springs (450)).

Referring again to FIG. 4B, as the movable plate (340) is pushed towardsthe second fixed plate (330) with an increasing spreading distance, “S”,from the initial gap G point, more force F is needed to further compressthe springs (450). This spreading distance “S” is equal to the decreasein the length of each compression spring (450) from their initial springfree length, L_(free) (length of the compression, spring (450) whenuncompressed), to a decreased length, L_(def) (the length of compressionsprings (450) in a given compressed state). Based on the equation ofHooke's Law as discussed above, this amount of spreading distance S issubstantially proportional to the amount of force exerted by eachcompression spring (450), wherein a total of the compression forcesapplied by the compression springs (450) will be substantially equal tothe amount of force applied by the hydraulic tool (10) when the movablejaw is extended at a given spreading distance S.

To determine an amount of spreading force that a given hydraulic tool isproviding while being tested using the test devices (300) or (400) asdiscussed above, a pressure/three marker or gauge may be employed thatprovides an indication to the amount of spreading force achieved. Forinstance, FIG. 4B generically illustrates a pressure gauge (480) thatmay be employed. The pressure gauge (480) generically depicts some formof distance markers that can be etched or mounted on the surface of thesupport plate (310) or otherwise provided on a separate marking elementthat is connected to the base plate (310), providing a plurality ofmarkers, P0, P1, P2, P3, etc., that are indicators of an amount ofspreading force applied based on the spreading distance S achieved.

In particular, the marking P0 represents an initial state in which thecontacting surface of the movable plate (340) is in an initial position(distance G from the first fixed plate (320)) with no force applied, tothe movable plate (340). As the movable plate (340) is pushed towardsthe second fixed plate (330), an amount of spreading force applied bythe tool being tested can be determined as the contact surface of themovable plate (340) reaches each subsequent marker, P1, P2, P3, etc.

For instance, assuming that the testing device (400) of FIG. 4B isconfigured such that the springs (450) provides a total spring force of10,000 psi, each marker P1, P2, P3, for example, can represent increasedincrements of 2500 psi, wherein marker P1 represents 2500 psi, marker P2represents 5000 psi, and marker P3 represents 7500 psi. In this manner,while a hydraulic tool is being tested, as the movable plate (340)reaches a given marker (P1, P2, P3, etc.), the individual testing thetool can have some indication as to the amount of spreading farce thetool is providing at that time.

FIGS. 5A and 5B are schematic views of a device for testing andmaintaining a hydraulic tool, according to another exemplary embodimentof the invention. In particular, FIG. 5A is a side schematic view ofanother embodiment of a test device (500) for testing and maintaining ahydraulic tool and FIG. 5B is a perspective view of the test device(500). The test device (500) shown in FIGS. 5A and 5B is similar to thetest device (400) of FIGS. 4A/4B in that the test device (500) includesa support base (310), a first fixed plate (320), a second fixed plate(330), a movable plate (340), and a plurality of separate springs (450)and bolts (or rods) (460) disposed between the movable plate (340) andthe second fixed plate (320). Moreover, similar to FIGS. 4A/4B, in thetest device (500) of FIGS. 5A/5B, the springs (450) are held in placebetween the movable plate (340) and the flat plate portion (334) of thesecond fixed plate (330) using a plurality of metallic studs (470) thatare fixedly connected (e.g. welded) to facing surfaces of the movableplate (340) and the flat plate portion (334) of the second fixed plate(330).

Furthermore, the test device (500) comprises a lower plate element (544)and a bracket element (546), wherein the lower plate element (544)slidably engages the bracket element (546). The lower plate element(544) is connected to the movable plate element (340). In one embodimentas specifically shown in FIG. 5B, the bracket element (546) is u-shapedbracket element which is welded to the base plate (310). The u-shapedbracket element (546) insertably receives the lower plate element (544).The collective structure of the lower plate element (544) and bracketelement (546) serves various purposes. For example, the lower plateelement (544) and bracket element (546) collectively serve as a means tostabilize the movable plate (340) as it slides hack and forth.

Moreover, since the lower plate element (544) is connected to themovable plate 340, the lower plate element (544) and bracket element(546) collectively serve as a means to hold the assembly of components(e.g., plate (340), springs (450), rods (460)) together in place on thebase plate (310). Indeed, FIG. 5B shows an initial state in which thecontacting surface of the movable plate (340) is in an initial position(represented by marking P0) at a distance G from the first fixed plate(320)) with no force applied to the movable plate (340). In this initialstate, the lower plate element (544) is extended through the u-shapedbracket element (546), and thus, the assembly of components (544, 340,450 and 460) are held in place in the test device (500) against the baseplate (310).

Furthermore, the lower plate element (544) and bracket element (546)collectively serve as a stopping means to limit the amount of distancethat the movable plate (340) can be pushed towards the second fixedplate (330) (so as to not over exert the compression springs (450)).Indeed, in one embodiment of the invention, the bracket element (546)can be positioned on the base plate (310) such that it serves as a stopelement that makes contact to the movable plate (340) as the movableplate (340) is pushed towards the second fixed plate (330) withsufficient spreading force while using the test device (500) is beingused. In another embodiment, the lower plate 544 can be sized (inlength) so that it serve as a stop element when it makes contact againstthe fixed plate element (344) as the movable plate (340) is pushedtowards the second fixed plate (330) with sufficient spreading forcewhile the test device (500) is being used.

In the embodiment shown in FIGS. 4A and 4B, a pair of upper and lowerrods (460) are implemented to provide added stability and support to theoverall test device assembly (500). In the embodiment of FIGS. 5A and5B, the pair of lower rod elements (460) may be eliminated, as the lowerplate element. (544) and the bracket element (546) provide added supportand stability to the overall assembly, as discussed above. In analternative embodiment, the upper and lower pairs of rods may beimplemented together with the lower plate element (544) and the bracketelement (546) provide even further support and stability to the overalltest device assembly (500).

FIGS. 6A and 6B are schematic views of a device for testing andmaintaining a hydraulic tool, according, to another exemplary embodimentof the invention. In particular, FIG. 6A is a side schematic view ofanother embodiment of a test device (600) for testing and maintaining ahydraulic tool and FIG. 6B is a perspective view of the test device(600). The test device (600) shown in FIGS. 6A and 6B is similar to thetest device (400) of FIGS. 4A/4B in that the test device (600) includesa support base (310), a first fixed plate (320), a second fixed plate(330) a movable plate (340), and a plurality of separate springs (450)and bolts for rods) (460) disposed between the movable plate (340) andthe second fixed plate (320). Moreover, similar to FIGS. 4A/4B, in thetest device (600) of FIGS. 6A/6B, the springs (450) are held in placebetween the movable plate (340) and the flat plate portion (334) of thesecond fixed plate (330) using a plurality of metallic studs (470) thatare fixedly connected (e.g., welded) to facing surfaces of the movableplate (340) and the flat plate portion (334) of the second fixed plate(330).

Furthermore, as shown in FIGS. 6A and 6B, the test device (600)comprises a first rod support element (610) and a second rod supportelement (620), which are fixedly connected (e.g., welded) to the baseplate (310). The first rod support element (610) comprises a firstaperture (611) and a second aperture (612) which insertably receive thelower and upper rods (460), respectively, on one side of the device(600). The second rod support element (620) comprises a first aperture(621) and a second aperture (622) which insertably receive the lower andupper rods (460) respectively, on the other side of the test device(600). The first and second rod support elements (610) and (020) servevarious purposes.

For example, the first and second rod support elements (610) and (620)collectively serve as a means to stabilize the overall assembly and holdthe rods (460) in vertical position with regard to the base plate (310).While the apertures (611, 612, 621 and 622) of the first and second rodsupport elements (610) and (620) are sized to allow the rods (460) tofreely slide back and forth there through, the first and second rodsupport elements (610) and (620) maintain the vertical position of therods (460) in relation to the base plate (310), which, in turn,maintains the movable plate (340) springs (450) in place in the overalltest device assembly (600).

Furthermore, the first and second rod support elements (610) and (620)may collectively serve as a stopping means to limit the amount ofdistance that the movable plate (340) can be pushed towards the secondfixed plate (330) (so as to not over exert the compression springs(450)). Indeed, in one embodiment of the invention, the first and secondrod support elements (610) and (620) can be positioned on the base plate(310) such that they act as stop demerits that make contact with themovable plate (340) as the movable plate (340) is pushed towards thesecond fixed plate (330) with sufficient spreading force while the testdevice (600) is being used.

FIGS. 7A and 7B are perspective views of a device (700) for testing andmaintaining a hydraulic tool, according to another exemplary embodimentof the invention. In general, the test device (700) shown in FIGS. 7Aand 7B is similar to previous embodiments in that the test device (700)includes as support base (710), as first fixed plate (720), a secondfixed plate (730), a movable plate (740), and a plurality of separatesprings (750) and bolts (or rods) (760) disposed between the movableplate (740) and the second fixed plate (730). The first fixed plate(720) comprises a first member (722) and a second member (724) whichform a right angle (90 degrees) fixed plate structure. The second fixedplate (730) comprises a first member (734) that is disposed parallel tothe movable plate (740) and one or more extended support members (732)are disposed perpendicular to the first member (734) to provide supportfor compressive forces that are applied to the second fixed plate (730).The supporting base plate (710) ma comprise a plurality of thru-holes(712) formed in corner regions of the base plate (710) so that the testdevice (700) can be bolted or screwed down to supporting work benchstructure, for example.

Moreover, the springs (750) are held in place between the movable plate(740) and the flat plate portion (734) of the second fixed plate (730)using a plurality of metallic studs (not specifically shown) that arefixedly connected (e.g., welded) to facing surfaces of the movable plate(740) and the flat plate portion (734) of the second fixed plate (730),as discussed above. In the embodiment of FIGS. 7A and 7B, one end ofeach guiding rod (760) is welded to a surface of the movable plate(740), while the opposite end of each guiding rod (760) slidably engagesthe first member (734) of the second fixed plate (730) and is held inplace with movable nuts that can be turned, which enables adjustment ofthe initial gap G between the movable plate (740) and the second member(724) of the first fixed plate (720).

As further shown in FIGS. 7A and 7B, the test device (700) furthercomprises a stop member (780) that is removably coupled to the movableplate (740). The stop member (780) comprises a first retaining member(782) and a second retaining member (784), which serve to retain thestop member (780) in position on a front side of the movable plate(740). The movable plate (740) comprises a plurality of slots (742) and(744), which interface with the second retaining member (784) on thebackside of the stopper member (780). The first retaining member (782)is a clip-type element that wraps around a top-side edge of the moveableplate (740) to maintain the stop member (780) against the front-sidesurface of the movable plate (740), while the second retaining member(784) (groove) and the slots (742) and (744) (tongue) provide a “tongueand groove” connection that holds the stop member (780) in place at someposition on the front-side of the movable plate (740), such asspecifically shown in FIG. 7A.

With the stop member (780) in position, there is a distance “L” betweenan inner surface of the stop member (780) and an inner surface of themember (722) of the first fixed plate (720). This distance “L” isadjusted depending on which slot (742) or (744) is used to engage thesecond retaining member (784) (groove) of the stop member (780). Theslots (742) and (744) are formed in the surface of the movable plate(740) in a spaced relation to the position of the fixed plate (720) sothat the distance “L” can be selected to accommodate standard sires ofjaw members of different commercially available hydraulic forcible entrytools that can be used with the device (700).

For example, when using the hydraulic forcible entry tool (10) of FIGS.1A and 1B with test device (700) in FIG. 7A, with the tool (10) in anon-extended position (as shown in FIG. 1A), the hydraulic forcibleentry tool (10) would be initially positioned with the sharp blade tip(18C) inserted in the initial gap between the movable plate (740) andthe fixed plate (720) and the top edge (18D) of the movable jaw member(18B) would be positioned adjacent to the inner side surface of the stopmember (780). As the hydraulic forcible entry tool (10) is actuated (asshown in FIG. 1B) with the piston (19) in an extended position, thebeveled tip of the fixed jaw (18A) would be pressed against the insideedge of the first fixed plate (720) and the movable jaw (18B) would bepressed against the surface of the movable plate (740). tinder highcompressive forces, there may be tendency for the fixed jaw (18A) toaccidently be disengaged from the fixed plate member (720) due to, e.g.,the beveled tip of the fixed jaw (18A). However, by use of the stopmember (780), the top edge (18D) of the movable jaw (18B) would bepressed up against the inside edge of the stop member (780), therebypreventing the tool (10) from accidently disengaging the test device(700) under high compressive forces, which would cause the movable plate(740) to snap back into position, and possibly cause injury to theindividual operating the test device (700). The stop member (780)provides a fixed distance “L” that corresponds to the dimensions of thejaw element (18) so as to prevent the tool (10) from accidentlydisengaging the test device (700) during a test operation.

Although FIG. 7B illustrates two slots, (742) and (744), the movableplate (740) can be formed with three or more slots to accommodate theblade dimensions of other standard hydraulic forcible entry tools.Moreover, in embodiments where the test device (700) is designed for aspecific standard hydraulic forcible entry tool requiring no adjustmentof the distance “L” between an inner surface of the stop member (780)and an inner surface of the member (722), the stop member (780) can befixedly mounted to the front-side surface of the movable plate (740) bye.g., welding. With the test device (700) embodiment shown in FIGS. 7Aand 7B, the device is formed with a wider profile (e.g., wider movableplate (740) and element (734)) which enables use of the stop member(780) with adjustable positions for various commercially availabletools. The wider profile enables the multiple springs (750) to belaterally positioned side by side, which also enables a reduction in thevertical profile of the test device (700).

FIGS. 8A and 8B are perspective views of a device for testing andmaintaining a hydraulic tool, according to another exemplary embodimentof the invention. FIGS. 8A and 8B illustrate a test device (800) whichis similar to the test device (700) shown in FIGS. 7A and 7B and, assuch, a detailed description of elements having the same referencelabels in FIGS. 8A/8B as in FIGS. 7A/7B will not be repeated. As furthershown in FIGS. 8A and 8B, the test device (800) comprises a stop member(880) that is removably coupled to a front side of the movable plate(740) using bolts (884). More specifically, in this embodiment, the stopmember (880) comprises a plurality of holes (882), and the movable plate(740) comprises a first set of threaded holes (842) and a second set ofthreaded holes (844), wherein the first and second set of threaded holes(842) and (844) are sized and spaced to align with the holes (882) ofthe stop member (880). In one embodiment, the stop member (880) isformed of steel (or some other metallic material) having a thickness ofabout ¼ inch, fur example.

FIG. 88 illustrates the stop member (880) mounted in position to thefront surface of the movable plate (740) using mounting bolts (884)which are inserted through the holes (882) of the stop member (880) andthreaded into the second set of threaded holes (844) of the movableplate (740). In this position, there is a distance “L” between a sideedge (880A) of the stop member (880) and an inner surface (722A) of themember (722) of the first fixed plate (720). This distance “'L” can beadjusted (e.g., shortened) by bolting the stop member (880) to the firstset of threaded holes (842) of the movable plate (740). In thisembodiment, the first and second set of thread holes (842) and (844) canbe formed in the movable plate (740) in a spaced relation to theposition of the fixed plate (720) so that the distance “L” can beselected to accommodate standard sizes of jaw members of differentcommercially available hydraulic forcible entry tools that can be usedwith the device (800), and thereby prevent the hydraulic forcible entrytool from accidently disengaging the test device (800) during a testoperation, such as described above. Although FIGS. 8A/8B illustrate twosets of threaded holes (842) and (844), the movable plate (740) can befarmed with three or more sets of threaded holes to accommodate theblade dimensions of other standard hydraulic forcible entry tools.

FIG. 9 is a perspective view of a device for testing and maintaining ahydraulic tool, according to another exemplary embodiment of theinvention. FIG. 9 illustrates a test device (900) which is similar tothe test device (700) shown in FIGS. 7A and 7B and, as such, a detaileddescription of elements having the same reference labels in FIG. 9 as inFIGS. 7A/7B will not be repeated. Moreover, FIG. 9 is similar to theembodiment discussed above in FIGS. 8A/8B in that the embodiment of FIG.9 utilizes a stop member, which can be removably bolted to a front sideof the movable plate (740) as a safety measure to prevent a hydraulicforcible entry tool from accidently disengaging the test device (900)during a test operation. such as described above.

However, as shown in FIG. 9 the movable plate (740) comprises one set ofthreaded holes (942), which can be used to bolt one of a plurality ofdifferent types of stop members e.g., stop members (980) or (990) (asshown in FIG. 9) to the front side of the movable plate (740). Forexample, the stop member (980) comprises a first set of holes (982) anda second set of holes (984), wherein the first and second sets of holes(982) and (984) are sized and spaced to align with the threaded holes(942) of the movable plate (740). In one embodiment, the stop member(980) is formed of steel (or some other metallic material) having athickness of about ¼ inch, for example.

In this embodiment, distance between side edge (980A) of the stop member(980) and the inner surface (722A) of the member (722) of the firstfixed plate (720) can be selected by bolting the stop member (980) tothe threaded holes (942) of the movable plate (740) using either thefirst set of holes (92) or the second set of holes (984) of the stopmember (980), wherein the different distances “L” can be designed toaccommodate standard sins of jaw members of different commerciallyavailable hydraulic forcible entry tools. Although the stop member (980)in FIG. 9 is shown to have two sets of holes (982) and (984), the stopmember (980) can be formed with three or more sets of holes toaccommodate the blade dimensions of other standard hydraulic forcibleentry tools.

As further shown in FIG. 9, the stop member (990) comprises a set ofgrooves (992), which are sized and spaced to align with the threadedholes (942) of the movable plate (740). In one embodiment, the stopmember (990) is formed of steel (or some other metallic material) havinga thickness of about ¼ inch, for example. In this embodiment, thedistance “L” between a side edge (990A) of the stop member (990) and theinner surface (722A) of the member (722) of the first fixed plate (720)can be adjusted by loosely bolting the stop member (990) to the threadedholes (942) of the movable plate (740), and then slidably adjusting thestop member (990) left or right (with the grooves (992) slidablyengaging the bolt shafts) to place the edge (990A) of the stop member(990) at a desired distance “L” from the inner surface (722A) of themember (722) of the first fixed plate (720), and then tighten the boltsto secure the stop member (990) in place.

The exemplary test devices described herein provide inexpensive designsthat can be used to test and maintain hydraulic tools such as hydraulicforcible entry tools, without the need for complex or expensive testequipment. Test devices according to exemplary embodiments of theinvention made of steel structures and strong, durable compressionsprings can provide significant durability for long lasting use fortesting and maintaining hydraulic tools.

Although illustrative embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those embodiments,and that various other changes and modifications may be affected thereinby one skilled in the art without departing from the scope or spirit ofthe invention.

I claim:
 1. A device for testing a hydraulic tool, comprising; a supportbase; a first fixed plate fixedly connected to the support base; asecond fixed plate fixedly connected to the support base; a movableplate, disposed between the first and second fixed plate; a stop membercoupled to a surface of the movable plate; and one or more compressionsprings disposed between the movable plate and the second fixed plate,wherein the movable plate and the first fixed plate are oriented withrespect to each other and adapted to engage a hydraulic tool beingtested, wherein the movable plate is adapted to be moved towards thesecond fixed plate upon actuation of the hydraulic tool and compress theone or more compression springs to provide a compression force thatprovides a test load for testing the hydraulic tool, and wherein thestop member is configured to prevent the hydraulic tool from accidentlydisengaging the device during testing.
 2. The device of claim 1, whereinthe first fixed plate comprises a first member and a second member,which form as right angle fixed plate structure.
 3. The device of claim1, wherein second fixed plate comprises a first member that is disposedparallel to the movable plate, and a plurality of extended supportmembers that are disposed perpendicular to the first member to providesupport for compressive forces that are applied to the second fixedplate as the movable plate is pushed towards the second fixed plate. 4.The device of claim 1, further comprising a force indicator element thatindicates an amount of spreading force applied by the hydraulic toolbased on a distance that the movable plate is moved towards the secondfixed plate.
 5. The device of claim 1, wherein the support base, firstfixed plate, second fixed plate, and movable plate are formed of piecesof planar steel having a thickness of about ½ inch.
 6. The device ofclaim 1, wherein each of the one or more compression springs are held inplace between the movable plate and the second fixed plate with a rodelement that longitudinally extends within an interior of thecompression spring.
 7. The device of claim 6, wherein one end of eachrod is fixedly attached to the movable plate and wherein another end ofeach rod slidably extends through a hole formed in portion of the secondfixed plate.
 8. The device of claim 1, wherein each of the one or morecompression springs are held in place between the movable plate and thesecond fixed plate using metallic studs that are fixedly connected tofixing surfaces of the movable plate and the second fixed plate.
 9. Thedevice of claim 8, wherein the studs are dimensioned to snuggly fitwithin the inner region of the one or more compression springs.
 10. Thedevice of claim 1, wherein the stop member is slidably coupled to thesort of the movable plate using a tongue and groove connection.
 11. Thedevice of claim 10, wherein the movable plate comprises at least onegroove that is configured to engage a tongue element formed on the stopmember and position a side edge oldie stop member at a predetermineddistance from as surface of the first fixed plate.
 12. The device ofclaim 10, wherein the movable plate comprises a plurality of grooves,wherein each groove is configured to engage a tongue element formed onthe stop member and position a side edge of the stop member at one of asplurality of predetermined distances from a surface of the firm fixedplate.
 13. The device of claim 1, wherein the stop member is removablycoupled to the surface of the movable plate using bolts.
 14. The deviceof claim 10, wherein the movable plate comprises at least one set ofthreaded holes that are aligned to at least one set of holes formed inthe stop member to enable the stop member to be bolted to the movableplate and position a side edge of the stop member at a predetermineddistance from a surface of the first fixed plate.
 15. A device fortesting a hydraulic tool, comprising: a support base; a first fixedplate fixedly connected to the support base; a second fixed platefixedly connected to the support base; a movable plate, disposed betweenthe first and second fixed plate; and one or more compression springsdisposed between the movable plate and the second fixed plate, whereinthe movable plate and the first fixed plate are oriented with respect toeach other and adapted to engage a hydraulic tool being tested.
 16. Amethod for testing a hydraulic tool, comprising: providing a device fortesting a hydraulic tool, the device comprising a support base, as firstfixed plate fixedly connected to the support base, a second fixed platefixedly connected to the support base, a movable plate, disposed betweenthe first and second fixed plate, and one or more compression springsdisposed between the movable plate and the second fixed plate; insertinga jaw member of hydraulic tool between the movable plate and the firstfixed plate; and actuating the hydraulic tool to cause the jaw member toopen and apply a spreading force between the movable plate and the firstfixed plate and cause the movable plate to move towards the second fixedplate and compress the one or more compression springs, whereincompression of the one or mete compression springs provides a test loadfor testing the hydraulic tool.